EP4038772A1

EP4038772A1 - Beam management

Info

Publication number: EP4038772A1
Application number: EP19947512.0A
Authority: EP
Inventors: Ahmad AWADA; Mihai Enescu; Timo Koskela; Sami-Jukka Hakola; Youngsoo Yuk
Original assignee: Nokia Technologies Oy
Current assignee: Nokia Technologies Oy
Priority date: 2019-10-03
Filing date: 2019-10-03
Publication date: 2022-08-10
Also published as: EP4038772A4; WO2021064277A1

Abstract

There is provided a method at an access node (110) providing a first cell (CELL 1), the method comprising: receiving, from a user equipment (120), over the first cell (CELL 1): a panel identifier indicating an antenna panel (1, 2, 3, 4) of the user equipment (120) and an indication that the identified antenna panel (2) is detecting radio beams from the first cell (CELL 1) and from at least one cell other than the first cell (CELL 2); and determining, based on the reception, at least one configuration for at least one of the user equipment and one or more of the cells.

Description

BEAM MANAGEMENT

TECHNICAL FIELD

Various example embodiments relate generally to beam management in wireless multi-connectivity communication scenario.

BACKGROUND

It is expected that future wireless communication devices, e.g. user equipment (UE), apply plurality of antenna panels. In a communication scenario where the UE communicates with multiple cells served by different nodes, there may be situations where the transmit beams to the UE are to be received by a same antenna panel of the UE. This may cause problems.

BRIEF DESCRIPTION

According some aspects, there is provided the subject matter of the in dependent claims. Some embodiments of the invention are defined in the depend ent claims. The embodiments that do not fall under the scope of the claims are to be interpreted as examples useful for understanding the disclosure.

LIST OF THE DRAWINGS

In the following, the invention will be described in greater detail with reference to the embodiments and the accompanying drawings, in which

Figure 1 presents a wireless communication network, according to an embodiment;

Figure 2A illustrates a scenario where the UE is connected to multiple cells, according to an embodiment;

Figure 2B shows a scenario where the UE is connected to multiple cells over one antenna panel, according to an embodiment;

Figures 3 depicts a method, according to an embodiment;

Figure 4A, 4B and 4C illustrate some embodiments for determining a reference signal transmission configuration;

Figures 5, 6A-6D, 7A and 7B depict some other embodiments for config uration determination;

Figure 8 shows a method for the user equipment, according to an em bodiment;

Figure 9 shows some methods for handling multiple connections at one antenna panel, according to some embodiments; and Figures 10 and 11 illustrates apparatuses, according to some embodi ments.

DESCRIPTION OF EMBODIMENTS

The following embodiments are exemplary. Although the specification may refer to "an", "one", or "some" embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodi ments), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embod iments.

Embodiments described may be implemented in a radio system, such as one comprising at least one of the following radio access technologies (RATs): Worldwide Interoperability for Micro-wave Access (WiMAX), Global System for Mobile communications (GSM, 2G), GSM EDGE radio access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunication System (UMTS, 3G) based on basic wideband-code division multiple access (W-CDMA), high-speed packet access (HSPA), Long Term Evolution (LTE), LTE-Advanced, and enhanced LTE (eLTE). Term 'eLTE' here denotes the LTE evolution that connects to a 5G core. LTE is also known as evolved UMTS terrestrial radio access (EUTRA) or as evolved UMTS terrestrial radio access network (EUTRAN). A term "resource" may refer to radio resources, such as a physical resource block (PRB), a radio frame, a subframe, a time slot, a subband, a frequency region, a sub-carrier, a beam, etc. The term "transmission" and/or "reception" may refer to wirelessly transmit ting and/or receiving via a wireless propagation channel on radio resources

The embodiments are not, however, restricted to the systems/RATs given as an example but a person skilled in the art may apply the solution to other communication systems provided with necessary properties. One example of a suitable communications system is the 5G system. The 3GPP solution to 5G is re ferred to as New Radio (NR). 5G has been envisaged to use multiple-input-multiple- output (M1MO) multi-antenna transmission techniques, more base stations or nodes than the current network deployments of LTE (a so-called small cell con cept), including macro sites operating in co-operation with smaller local area ac cess nodes and perhaps also employing a variety of radio technologies for better coverage and enhanced data rates. 5G will likely be comprised of more than one radio access technology / radio access network (RAT/RAN), each optimized for certain use cases and/or spectrum. 5G mobile communications may have a wider range of use cases and related applications including video streaming, augmented reality, different ways of data sharing and various forms of machine type applica tions, including vehicular safety, different sensors and real-time control. 5G is ex pected to have multiple radio interfaces, namely below 6GHz, cmWave and mmWave, and being integrable with existing legacy radio access technologies, such as the LTE.

The architecture in LTE networks may be distributed in the radio and centralized in the core network. The low latency applications and services in 5G require to bring the content close to the radio which leads to local break out and multi-access edge computing (MEC). 5G enables analytics and knowledge genera tion to occur at the source of the data. This approach requires leveraging resources that may not be continuously connected to a network such as laptops, smartphones, tablets and sensors. MEC provides a distributed computing environ ment for application and service hosting. It also has the ability to store and process content in close proximity to cellular subscribers for faster response time. Edge computing covers a wide range of technologies such as wireless sensor networks, mobile data acquisition, mobile signature analysis, cooperative distributed peer- to-peer ad hoc networking and processing also classifiable as local cloud/fog com puting and grid/mesh computing, dew computing, mobile edge computing, cloud let, distributed data storage and retrieval, autonomic self-healing networks, remote cloud services, augmented and virtual reality, data caching, Internet of Things (massive connectivity and/or latency critical), critical communications (autono mous vehicles, traffic safety, real-time analytics, time-critical control, healthcare applications). Edge cloud may be brought into RAN by utilizing network function virtualization (NVF) and software defined networking (SDN). Using edge cloud may mean access node operations to be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head or base station comprising radio parts. Network slicing allows multiple virtual networks to be created on top of a common shared physical infrastructure. The virtual networks are then custom ised to meet the specific needs of applications, services, devices, customers or op erators.

For 5G networks, it is envisaged that the architecture may be based on a so-called CU-DU (central unit - distributed unit) split, where one gNB-CU controls several gNB-DUs. The term 'gNB' may correspond in 5G to the eNB in LTE. The gNBs (one or more) may communicate with one or more UEs 120. The gNB-CU (central node) may control a plurality of spatially separated gNB-DUs, acting at least as transmit/receive (Tx/Rx) nodes. In some embodiments, however, the gNB-DUs (also called DU) may comprise e.g. a radio link control (RLC), medium access con trol (MAC) layer and a physical (PHY) layer, whereas the gNB-CU (also called a CU) may comprise the layers above RLC layer, such as a packet data convergence pro tocol (PDCP) layer, a radio resource control (RRC) and an internet protocol (IP) layers. Other functional splits are possible too. It is considered that skilled person is familiar with the OSI model and the functionalities within each layer.

Some other technology advancements probably to be used are Soft ware-Defined Networking (SDN), Big Data, and all-IP, to mention only a few non limiting examples. For example, network slicing may be a form of virtual network architecture using the same principles behind software defined networking (SDN) and network functions virtualisation (NFV) in fixed networks. SDN and NFV may deliver greater network flexibility by allowing traditional network architectures to be partitioned into virtual elements that can be linked (also through software) . N et- work slicing allows multiple virtual networks to be created on top of a common shared physical infrastructure. The virtual networks are then customised to meet the specific needs of applications, services, devices, customers or operators.

The plurality of gNBs (access points/nodes), each comprising the CU and one or more DUs, may be connected to each other via the Xn interface over which the gNBs may negotiate. The gNBs may also be connected over next genera tion (NG) interfaces to a 5G core network (5GC), which may be a 5G equivalent for the core network of LTE. Such 5G CU-DU split architecture may be implemented using cloud/server so that the CU having higher layers locates in the cloud and the DU is closer to or comprises actual radio and antenna unit. There are similar plans ongoing for LTE/LTE-A/eLTE as well. When both eLTE and 5G will use similar ar chitecture in a same cloud hardware (HW), the next step may be to combine soft ware (SW) so that one common SW controls both radio access networks /technol ogies (RAN/RAT). This may allow then new ways to control radio resources of both RANs. Furthermore, it may be possible to have configurations where the full pro tocol stack is controlled by the same HW and handled by the same radio unit as the CU.

It should also be understood that the distribution of labour between core network operations and base station operations may differ from that of the LTE or even be non-existent. Some other technology advancements probably to be used are Big Data and all-IP, which may change the way networks are being con structed and managed. 5G (or new radio, NR) networks are being designed to support multiple hierarchies, where MEC servers can be placed between the core and the base station or nodeB (gNB). It should be appreciated that MEC can be ap plied in 4G networks as well.

5G may also utilize satellite communication to enhance or complement the coverage of 5G service, for example by providing backhauling. Possible use cases are providing service continuity for machine-to-machine (M2M) or Internet of Things (IoT) devices or for passengers on board of vehicles, or ensuring service availability for critical communications, and future rail-way/maritime/aeronauti- cal communications. Satellite communication may utilize geostationary earth orbit (GEO) satellite systems, but also low earth orbit (LEO) satellite systems, in partic ular mega-constellations (systems in which hundreds of (nano) satellites are de ployed). Each satellite in the mega-constellation may cover several satellite-ena bled network entities that create on-ground cells. The on-ground cells may be cre ated through an on-ground relay node or by a gNB located on-ground or in a satel lite.

The embodiments may be also applicable to narrow-band (NB) Inter- net-of-things (IoT) systems which may enable a wide range of devices and services to be connected using cellular telecommunications bands. NB-IoT is a narrowband radio technology designed for the Internet of Things (IoT) and is one of technolo gies standardized by the 3rd Generation Partnership Project (3GPP). Other 3GPP IoT technologies also suitable to implement the embodiments include machine type communication (MTC) and eMTC (enhanced Machine-Type Communication). NB-IoT focuses specifically on low cost, long battery life, and enabling a large num ber of connected devices. The NB-IoT technology is deployed "in-band" in spectrum allocated to Long Term Evolution (LTE) - using resource blocks within a normal LTE carrier, or in the unused resource blocks within an LTE carrier’s guard-band - or "standalone" for deployments in dedicated spectrum.

Figure 1 illustrates an example of a communication system to which em bodiments of the invention may be applied. The system may comprise a control node 110 providing one or more cells, such as cell 100, and a control node 112 providing one or more other cells, such as cell 102. Each cell may be, e.g., a macro cell, a micro cell, femto, or a pico cell, for example. In another point of view, the cell may define a coverage area or a service area of the corresponding access node. The control node 110, 112 may be an evolved Node B (eNB) as in the LTE and LTE-A, next generation Node B (ng-eNB) as in eLTE, gNB of 5G, or any other apparatus capable of controlling radio communication and managing radio resources within a cell. The control node 110, 112 may be called a base station, network node, or an access node.

The system may be a cellular communication system composed of a ra dio access network of access nodes, each controlling a respective cell or cells. The access node 110 may provide user equipment (UE) 120 (one or more UEs) with wireless access to other networks, such as the Internet. The wireless access may comprise downlink (DL) communication from the control node to the UE 120 and uplink (UL) communication from the UE 120 to the control node.

Additionally, although not shown, one or more local area access nodes may be arranged such that a cell provided by the local area access node at least partially overlaps the cell of the access node 110 and/or 112. The local area access node may provide wireless access within a sub-cell. Examples of the sub-cell may include a micro, pico and/or femto cell. Typically, the sub-cell provides a hot spot within a macro cell. The operation of the local area access node may be controlled by an access node under whose control area the sub-cell is provided. In general, the control node for the small cell may be likewise called a base station, network node, or an access node.

The term "terminal device" or "UE" refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wire less local loop phones, a tablet, a wearable terminal device, a personal digital assis tant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback ap pliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an In ternet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a con sumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms "terminal device", "communication device", "terminal", "user equipment" and "UE" may be used interchangeably.

In the case of multiple access nodes in the communication network, the access nodes may be connected to each other with an interface. LTE specifications call such an interface as X2 interface. For IEEE 802.11 network (i.e. wireless local area network, WLAN, WiFi), a similar interface Xw may be provided between ac cess points. An interface between an eLTE access point and a 5G access point, or between two 5G access points may be called Xn. Other communication methods between the access nodes may also be possible. The access nodes 110 and 112 may be further connected via another interface to a core network 116 of the cellular communication system. The LTE specifications specify the core network as an evolved packet core (EPC), and the core network may comprise a mobility manage ment entity (MME) and a gateway node. The MME may handle mobility of terminal devices in a tracking area encompassing a plurality of cells and handle signalling connections between the terminal devices and the core network. The gateway node may handle data routing in the core network and to/from the terminal devices. The 5G specifications specify the core network as a 5G core (5GC), and there the core network may comprise e.g. an access and mobility management function (AMF) and a user plane function/gateway (UPF), to mention only a few. The AMF may handle termination of non-access stratum (NAS) signalling, NAS ciphering & integ rity protection, registration management, connection management, mobility man agement, access authentication and authorization, security context management. The UPF node may support packet routing & forwarding, packet inspection and QoS handling, for example.

Figure 2A illustrates a scenario where the UE 120 is having multiple connections to multiple cells. It is assumed that the UE 120 is equipped with four antenna panels (or simply panels or UE panels). The number four is used for illus tration purposes only and the UE 120 could have any number of at least one panel. Each UE panel is assumed to be equipped with one radio frequency (RF) chain (im plying analog RF beamforming) . This may allow forming one beam (may be a single or dual-polarized beam) at a time per panel for communicating with the network.

Let us further assume that the access nodes 110 and 112 are gNBs 110 and 112. It is assumed that the gNBs 110, 112 each provide three cells (also a non limiting example number). The coverage of the cells may be provided via one or more transmission and reception points (TRPs). In this example illustration, the UE 120 is served by a TRP 1 and 2 from a cell 1 served by the gNB 110 and by TRP 3 that is served by a cell 2 of the gNB 112. In another scenario, each cell may have only one TRP. Each cell 1 and 2 may maintain its own physical (PHY) / Medium Access Control (MAC) protocol stack layers and, consequently, beam management related procedures are handled by each cell independently.

In Figure 2A, the UE communicates with the TRP2 of the gNB 110 and with the TRP3 of the gNB 112 on different beams formed by UE panels 2 and 3, respectively. Due to UE rotation/mobility, the UE 120 may need to communicate with the TRP 2 and TRP 3 on the same panel 2 but with different reception (Rx) and/or transmission (Tx) beams. This may not be possible simultaneously due to analog beamforming where only a single beam can be formed by one panel at a time. For illustration, Fig. 2B shows an example where the UE has rotated some degrees counter-clock wise (compared to Figure 2A) and the receive/transmit beam from TRP 3 switches from UE panel 3 to panel 2, thus conflicting with the receive/transmit beam that is set with respect to the TRP 2 from Cell 1 of gNB 110.

Thus, one problem the invention at least partially aims to solve is how to handle situations where at least two TRPs from different cells/gNBs configure beams to be applied on same UE panel.

NR Rel. 15 has considered beam management procedures for the case when the UE is served by one TRP from a single cell/gNB. Later, NR Rel. 16 work item on multiple input multiple output (MIMO) enhancements is introducing new procedures for supporting multi-TRP transmission from a same gNB to improve reliability and robustness (by leveraging diversity from multiple links). It has been discussed that the UE may include a panel identifier (ID) when reporting measure ments on Synchronization Signal/Physical Broadcast Channel (SS/PBCH) blocks or Channel State Information Reference Signal (CSI-RS). In the scenario where the UE is served by multiple TRPs from the same cell/gNB, the panel ID information in cluded in the measurement report can be used by the serving cell to configure transmission of beams that can be received by the UE on different panels. This so lution may work well as long as the TRPs are connected to same serving/gNB. How ever, it may not be enough in the scenario depicted in Figure 2B, where the TRPs belong to different cells/gNBs. This is because the beam management procedures for the individual radio links may be handled by each cell separately and they are not coordinated.

Another related issue to Figure 2B is how to tune a radio beam of UE panel 2 to efficiently communicate with two different TRPs (e.g. TRPs 2 of the gNB 110 and the TRP 3 of the gNB 112). A radio beam may be a spatially limited wireless radio beam (formed by e.g. beamforming, beam steering, beam switching) from an antenna array /panel. For example, some downlink beam management procedures that are defined in NR Rel. 15 may be summarized as:

• P-1: used to enable UE measurement on different TRP Tx beams to support selection of TRP Tx beams/UE Rx beam(s) o For beamforming at a TRP, it typically includes an intra/in- ter-TRP Tx beam sweep from a set of different beams. For beamforming at UE, it typically includes a UE Rx beam sweep from a set of different beams.

• P-2: used to enable UE measurement on different TRP Tx beams to possibly change inter /intra-TRP Tx beam(s) o From a possibly smaller set of beams for beam refinement than in P-1. Note that P-2 can be a special case of P-1.

• P-3: used to enable UE measurement on the same TRP Tx beam to change UE Rx beam in the case UE uses beamforming

The first procedure P-1 may be used for initial TRP transmit and UE re ceive beam selection. The second procedure P-2 may be used to enable the refine ment of the TRP transmit beam, whereas P-3 may be used for re-fining the UE re ceive beam in cases where the UE is provided with a possibility to try different re ceive beams to receive a certain transmit beam.

For P-3, the serving TRP configures the UE by means of RRC signaling with the set of channel state information - reference signal (CSI-RS) resource (s) to measure and trigger the UE to perform measurements, e.g. by means of lower layer signaling (MAC control element (CE) for semi-persistent CSI-RS or downlink con trol information (DCI) for aperiodic CSI-RS). In a proposal, the TRP may repeat the transmission of the CSI-RS while the UE is sweeping its receive beam. Once the re ceive beam sweep is completed, the UE may adjust its receive beam to a better one by selecting the one that leads to the highest received signal strength or quality. During the receive beam sweep, the UE may not be able to 1) receive or transmit user data efficiently or 2) communicate at all to the network as the receive beam may be pointing to some directions which do not collect much signal power from the serving TRP. For the former case, smaller modulation and coding scheme (MCS) may have to be used if the TRP would like to keep the radio communication on going while sweeping the receive beam. In addition, demodulation reference signal (DMRS) overhead may increase since each beam direction should be provided with a DMRS in order to perform appropriate channel estimation.

As described above, beam management procedures may be handled by each cell independently in the scenario of Figure 2B. Thus, it may happen that each TRP triggers the measurements for receive beam sweep (for enhanced UE’s Rx beam) at different time instants which is not optimal in case the TRP transmit beams are received by the UE on the same panel. For clarity, consider the scenario of Figure 2B: TRP 2 of the gNB 110 triggers Rx beam sweep which lasts T [ms]. Later, TRP 3 of the gNB 112 triggers Rx beam sweep which lasts T [ms] as well. During this total time 2T [ms], the UE may not be able to communicate with the other TRP on the UE panel 2 while sweeping the receive beam for the TRP that triggered the measurements for receive beam sweep. The issue of triggering re ceive beam sweep independently from different cells/TRPs of different gNBs may occur often in multi-connectivity scenarios e.g. at high carrier frequencies, as the UE may typically be equipped with multiple receive panels and connected to mul tiple TRPs of different gNBs.

Thus, another problem is how to enhance a receive beam sweep, such that adverse impacts of the receive beam sweep (interruption in radio communi cation or increased of radio resource usage due to smaller MCS) are reduced, e.g. in a scenario where the UE 120 has multiple panels and may communicate via one UE panel 2 with multiple cells/TRPs (e.g. TRP 2 of gNB 110 and TRP 3 of gNB 112), as shown in Figure 2B.

The problems described above may relate to beam management in dual (or multi) -connectivity scenario, e.g., intra-frequency or inter-frequency, where the UE 120 is connected to multiple cells served by different gNBs 110, 112. The gNBs may be connected by a logical interface, such as Xn. In an embodiment, one of the gNBs, e.g., gNB 110, may act as master node for the UE connection and interact with a secondary gNB 112. To at least partially tackle these inter-related problems, there is proposed a solution for a coordinated beam management. Although applicable to many networks, we will in the following examples focus on 5G, for the sake of simplicity.

Figure 3 depicts an example method. The method may be performed by an access node, such as the access node 110, providing e.g. at least the cell 1 (let us call this a first cell) of Figure 2B. As shown in Figure 3, the node 110 may in step 300 receive from the UE 120 over the first cell at least two information elements (IE). In an embodiment, the message of step 300 is carried over a physical uplink control channel (PUCCH) or over a physical uplink shared channel (PUSCH). The UE 120 may be equipped with multiple transmit/receive panels (=antenna panel). However, the UE 120 may only provide one beam per transmit/receive panel, possibly due to analog beamforming restrictions. The user equipment may detect radio beams from a plurality of cells at one antenna panel, e.g. from cell 1 of gNB 110 (=the first cell) and cell 2 of gNB 112. The UE 120 may participate in multi connectivity from multiple different cells, which may originate from the same gNB or different gNBs.

These lEs may comprise a panel identifier of an antenna panel, that may be associated with a measurement report. In this specific example, the UE 120 may report an ID for the panel 2, as that is used by the UE 120 for performing measure ments from a wireless radio communication network to which gNB 110, 112 be long to. Also, panel 1 may be used in Figure 2B for radio measurements, and panel 1 may be reported to the gNB 110, as well as indication of any other panel the UE 120 uses for radio measurements.

The indicated panel identifier is unique among the cells (e.g. cell 1 of gNB 110 and cell 2 of gNB 112) providing the multi-connectivity. This means that the UE panel 2 is UE panel 2 for every associated cell of the multi-connectivity. That is, the panel ID is defined such it is interpreted in the same way by all the cells/gNBs involved in the dual/multi-connectivity. As an example, beams measured for gNB 110 and gNB 112 using panel ID 2 in Figure 2B are indicated to the network (i.e. to the gNBs/cells) as being measured by the same panel on the UE side (but with po tentially different beams).

The lEs may further comprise an indication that the identified trans mit/receive panel (e.g. panel 2 in this example) is detecting radio beams from the first cell and from at least one cell other than the first cell. Alternatively or in addi tion to, indication may indicate that the identified antenna panel is maintaining connection to at least one cell (cell 2 of gNB 112) other than the first cell (cell 1 of gNB 110), in addition to the first cell. For example, each identified panel ID is ac companied with an IE on whether the corresponding panel ID is maintaining con nection to at least one cell, other than the one to which the UE panel ID is reported. In the example of Figure 2B, the UE 120 may report also UE panel 1 to gNB 110, but here the indication would indicate that this UE panel ID 1 is not maintaining con nection to any other cell. The indication may in an embodiment be e.g. a flag or a bit transmitted to a specific gNB (per reported beam) indicating that panel is used for communication also with another cell. In alternative implementation, the indi cation is only provided in case the panel ID is used for maintaining connection to at least one other cell. This may reduce signaling overhead in cases where no dual- or multi-connectivity is associated with an identified panel. When UE is configured with multi-connectivity it may implicitly assume the reporting mode (including the reporting format) corresponding to the panel ID and the indication that are re ported in step 300.

In an embodiment, the at least two different cells are provided by at least two different access nodes, e.g. nodes 110 and 112 as in Figure 2B. However, in another embodiment, the at least two different cells are provided by the same gNB, e.g. 110. In this case the cells may still maintain its own physical PHY/MAC protocol stack layers and, consequently, beam management related procedures are handled by each cell independently. This may consequently trigger the need for the embodiments presented herein. In yet one embodiment, the cells are provided by a same CU but by different DUs, which may likewise trigger the need for the em bodiments presented herein. In such cases, the inter-node communication (e.g. over Xn), as discussed later, may be negotiation between the DUs or TRPs over the same gNB 110, for example.

In an embodiment, the UE 120 may also report and the gNB 110 provid ing the first cell 1 may receive at least one cell identifier (e.g. physical cell identifier, PCI) identifying the at least one cell other than the first cell. In this way, the receiv ing gNB 110 may determine which at least one other cell is connected to the iden tified panel ID 2. Although the description shows two cells (1 of gNB 110 and 2 of gNB 112), there may be more than two cells that are connected to the same UE panel 2. For the sake of simplicity, only dual-connectivity scenario is depicted in Figure 2B.

In an embodiment, the lEs comprising the UE panel identifier and the indication/indicator of multi-connectivity are received in a radio measurement re port message. That is the UE 120 includes the lEs in the measurement report that may be used for beam reporting to the network, in addition to N strongest layer 1 reference signal received power (Ll-RSRP) measurements (or any other measure ment quantity) of e.g. SS/PBCH blocks and/or CS1-RS. The identified unique panel ID may be the panel on which the LI RSRP (or equivalent) measurements have been carried out.

In step 302 of Figure 3, the node 110 may determine, based on the re ception of the panel ID and the indication indicating multi-connectivity on the panel ID, at least one configuration for at least one of the UE 120 and one or more of the cells. In other words, one or more configurations for the UE 120 may be mod ified or otherwise determined, one or more configurations for the cell 1 of the gNB 110 may be modified or otherwise determined, and/or one or more configurations for the cell 2 of the gNB 112 may be modified or otherwise determined. These dif ferent options will be discussed next.

In an embodiment of step 302, those cells, whose transmit beams are received by the UE 120 using the same panel, may coordinate for triggering of a receive beam sweep (e.g. in multi-cell P3 procedure) at the UE 120 such that it is performed once for all involved TRPs. Accordingly, as shown in Figures 4A-4C, the node 110 may determine in step 400, based on the reception of the IEs, a reference signal transmission configuration (RS Tx configuration) for the first cell and/or for at least one other cell such that reference signals are transmitted for the identified antenna panel substantially simultaneously from the first cell and from the at least one other cell. The reference signal configuration may define e.g. time and fre quency locations of the reference signals to be transmitted.

Thereafter, in step 402, the node 110 may send the reference signals via the relevant TRP 2 of cell 1 of gNB 110 to the UE 120 for the identified antenna panel based on the determined reference signal transmission configuration. In step 404 the node 110 may trigger a receive beam sweep 412 (see Figure 4B) at the UE 120 on the identified antenna panel based on the determined reference signal transmission configuration. The triggering of the CSI-RS measurement may be per formed by any cell involved in the dual-connectivity. The beam sweeping may be accomplished by beamforming, for example.

In an embodiment, the determining of the RS Tx configuration is based on the node 110 negotiating with at least one other access node providing the at least one other cell. For example, the gNB 110 may negotiate over Xn with the gNB 112 providing the cell 2 for the same identified panel ID 2. As said, the gNB 110 may know that it needs to agree on the RS Tx configuration with the gNB 112, as the gNB 110 may have received a cell identifier of the cell 2. In other words, the gNBs 110 and 112 involved in dual-connectivity may coordinate using the Xn in terface e.g. about time/frequency locations (e.g. indices of subframes/slots/sym bols or set of symbols) that they shall use for repeating their CSI-RS transmissions. In one embodiment, the time locations can be expressed in terms of subframe/slot indices and/or number of subframes/slots. In an embodiment, the gNB 110 may indicate to the other gNB(s) 112 the configuration of CSI-RSs whose transmissions will be repeated for the UE’s 120 receive beam sweep and the corresponding UE panels (e.g. panel ID 2) for measuring these CSI-RSs. In an embodiment, the TRPs may be confined within the same set of PRBs (to confine/limit the transmission bandwidth) but the reference signals may be transmitted on different frequency locations in the same symbol to avoid interference.

Using this information, the other gNB(s) 112 may determine which CSI- RS transmission to repeat in parallel, e.g., those CSI-RS transmissions that are to be measured on the same UE panel ID 2. In this way, the TRP 2 of cell 1 of gNB 110 and the TRP 3 of cell 2 of gNB 112 may transmit their respective CSI-RSs in parallel, so that the UE 120 may measure those with one Rx beam sweep. As an example, the network may configure specific sets of CSI-RS (transmitted using set of TRPs of dif ferent gNBs) for joint beam sweeping and use lower layer signaling, such as DCI or MAC CE, to trigger the Rx beam sweep 412 and related measurement and reporting.

In an embodiment, either the TRP 2 of gNB 110 or the TRP 3 of gNB 112 modifies its RS transmission configuration as a response to the negotiation, in or der to reach a common understanding of the to-be-transmitted reference signals and resources with respect to this identified UE panel 2.

In an embodiment the reference signal transmission configuration of the first cell (from the relevant TRP) comprises repetitively transmitting the refer ence signals. In an embodiment the reference signal transmission configuration of the at least one other cell (from the relevant TRP(s)) comprises repetitively trans mitting the reference signals. Performing the transmission repetitively allows the UE 120 with enough time to sweep its RX beam across relevant spatial domain and measure the beams from both cells.

In an embodiment, the determined or agreed reference signal transmis sion configuration of the first cell comprises transmitting the reference signals in parallel with the at least one other cell. Doing the transmission in parallel may re duce time needed for the beam tuning.

In an embodiment, the determining of the RS TX configuration further comprises indicating the reference signal transmission configuration of the first cell and/or of the at least one other cell to the user equipment. This is shown in Figure 4B (which is a simplified representation of Figure 2B) with reference nu meral 410. Although shown as being transmitted from the gNB 110, the transmis sion of the determined (common) CSI-RS configuration could in addition or alter natively be sent from the gNB 112 to the UE 120. In this way the network may con figure the UE 120, e.g. by means of RRC signaling, the CSI-RS configuration of dif ferent TRPs belonging to different gNBs 110, 112 that the UE 120 shall measure while performing a receive beam sweep 412. The configuration may indicate e.g. that the CSI-RS transmissions of the TRPs in different gNBs 110, 112 are to be re peated and may specify as well which CSI-RS to measure on each UE panel. This may limit the UE sweep on specific UE panel(s) and/or may allow a single configu ration to configure multiple sweeps and divide them in a panel-based manner. This may be helpful e.g. if the UE 120 runs more than one receive sweep on different panels (limit the number of CSI-RS to measure per panel). Even though some em bodiments use CSI-RS or SS/PBCH blocks as example signals to be measured, any other reference signal that the UE 120 may detect may be used.

By using the coordinated CSI-RS transmissions, the time to successfully complete the receive beam sweep on a given UE panel may be reduced by the num ber of TRPs whose transmit beams are received on the same UE panel. Conse quently, this may shorten the time duration in which the UE would not be able to communicate with other TRP while performing receive beam sweep.

Let us take one more look at the proposal of Figure 4A in form of a sig naling flow diagram of Figure 4C. In step 420 the UE is configured with DC via TRP 2 to cell 1 of gNB 110 and via TRP 3 to cell 2 of gNB 112.

The UE in step 422 sends e.g. a LI measurement report to the gNB 110. The UE may also send a measurement report to gNB 112 if so configured, but for simplicity transmission to gNB 110 is shown. The measurement report may com prise e.g. Ll-RSRP measurements of SS/PBCH blocks and/or CSI-RS of celll/gNB 110 (and possibly of cell2/gNB 112), the UE panel ID (as in step 300) correspond ing to the reported measurements and the indication. The PCI of the cell 2 /gNB 112 may be identified in the message. As such, this step may resemble step 300 of Fig ure 3. In alternative embodiment, the panel ID and the indication may be transmit ted without any measurement report.

In step 424 gNB 110 may initiate the negotiation to determine the ref erence signal transmission configuration among the cells associated with the multi connectivity. In this example, the gNB 110 may a request for CSI-RS transmission coordination to gNB 112 providing cell 2. It needs to be noted that CSI-RS is used merely as an example and any other signal suitable for performing measurements by the UE 120 may be used instead or in addition. The request of step 424 may comprise e.g. CSI-RS resource configuration proposal (including e.g. CSI-RS indices and/or time-frequency locations), and the UE panel that is relevant for this request (i.e. panel 2).

In step 426, the gNB 112 may send either acknowledgement (ACK) or non-acknowledgement (NACK). This may comprise e.g. CSI-RS resource configura tion for the indicated time and frequency locations, and the UE panel that is rele vant for this response message. In an embodiment of step 426, the gNB 112 may provide a CSI-RS configuration for different time locations than those proposed by gNB/cell 1. In such case, it may be up to the gNB 110 to adopt this proposal or de cline it.

In step 428, the gNB 110 detects either ACK or NACK from the response message. If the determination is NACK, then both gNBs 110, 112 may perform the CSI-RS transmission in the legacy manner (where both send their own CSl-RSs and trigger the beam sweep of the UE independently from each other). However, if the response indicates ACK, then the process proceeds to step 430.

In step 430, the gNB 110 sends an indication of the coordinated/agreed CSI-RS Tx configuration to the UE 120. This message may comprise e.g. CSI-RS con figuration of TRPs from different gNBs (e.g. the indices of CSI-RS and/or the time- frequency resources), the UE panel that is relevant for this Rx beam sweep, and possibly an indication that the CSl-RSs from these gNBs will be repeated and/or sent in parallel. The message may be an RRC message, for example.

In step 432, the gNB 110 may then trigger the receive beam sweep 412 at the UE 120. This may happen with a lower layer triggering message.

In an embodiment, the configuration indication and the triggering to perform the CSI-RS measurement may be performed by another gNB (e.g. gNB 112) involved in dual-connectivity but which did not initiate the request in step 424.

As a response to steps 430 and 432, the gNBs 110, 112 may transmit the CSI-RS according to the determined configuration and the UE 120 may in step 434 perform the receive beam sweep 412 (e.g. sweep the receive beam across a prede termined spatial domain) and measure the CSI-RS of different TRPs on the indi cated time-frequency locations. This may comprise e.g. detecting RSRP for each Rx beam direction of the beam sweep 412.

In step 436, the UE 120 may determine the best receive beam for each transmitting TRP. The best Rx beam may be one common Rx beam that may receive data from both/all relevant TRPs, or one Rx beam for one TRP and another Rx beam for another TRP. In an embodiment, the UE may configure the antenna array/panel so that it forms two different beams pointing to different TRPs. E.g. the UE 120 may sweep through a specific set of narrow beams, or sweep through a smaller set of spatial directions with wider beams (and determine that single wide beam may be used). The UE 120 may, based on reciprocity, apply the determined beam/beams also for transmission to these TRPs.

Let us then look at other options (than the ones proposed in Figures 4A- 4C) for step 302 of Figure 3. Some embodiments 500-506 are disclosed in Figure 5. In option 500, the gNB 110 may determine, as the at least one configu ration, a beam configuration for at least one of the cells. The beam configuration comprises at least one of the cells to refrain from setting up a beam that the UE 120 would connect with the identified transmit/receive panel 2. That is, by using the reception of step 300, the gNB 110 may avoid configuring a transmit TRP beam that is received on a UE panel 2 that is already maintaining a radio communication with another TRP. For instance, the serving cell 1 of gNB 110 may configure a beam from another TRP that can be received on a UE panel that is not maintaining any radio communication. This may not require any inter-cell negotiations.

If the cell involved in dual-connectivity (e.g. cell 1 via TRP 2) decides to go ahead and configure/maintain the TRP 2 transmit/receive beam that is con nected to UE panel 2 maintaining a radio communication also with another TRP of a different cell/gNB (e.g. TRP 3 of cell 2 of gNB 112), e.g. due to any other TRP beams not being sufficiently detectable by the UE 120, the gNB 112 of cell 1 may perform another action. These are considered next.

In an embodiment, as shown in Figure 6A (which is a simplified repre sentation of Figure 2B), the determination of the beam configuration may comprise the gNB 110 instructing or requesting the cell 2 of gNB 112 to avoid configuring a serving beam for the UE 120 for the identified panel 2. In this illustrated example, the gNB 112 accepted the request and established a beam with TRP 1 of cell 2 which allows communicating with UE’s panel 4, instead of the panel 2. As a result, the UE 120 has at maximum only one cell to communicate with per antenna panel.

In an embodiment, the gNB 110 may determine in option 502, based on the reception of the panel ID and the indication of whether this panel ID is used for multi-connectivity (in step 300), a time-division multiplexing (TDM) configuration between the first cell and at least one other cell such that at a time only one cell communicates with the identified transmit/receive panel 2 of the UE 120. That is, the cells may start applying TDM to communicate with both TRPs of different gNBs using the same panel 2 of the UE 120. Thereafter, the UE may communicate follow ing the TDM pattern configuration provided by the network (from either of the cells). This is shown in Figure 6B where the UE uses one of two beams from panel 2 at a time and the cells take turns in communicating with the UE 120. Alternatively, the UE 120 may use a one single beam capable of receiving/transmitting data with both cells, while the cells may obey the determined TDM configuration.

In an embodiment, determining the at least one configuration com prises determining a beam configuration for at least one of the cells, wherein the beam configuration comprises at least temporarily suspending at least one beam towards the identified panel 2, as depicted in option 504 of Figure 5. In this way, the network (e.g. the gNB 110) may use only one of the two radio links for trans mission/reception and to suspend the other one. Figure 6C shows this embodi ment, where the gNB 110 has suspended (marked by cross) its radio beam from TRP 2 of cell 1. The suspended radio link may be resumed later, e.g. once the beam from the serving TRP 2 of cell 1 may be handled by another UE panel that is not maintaining radio communication to other cell(s). This option may take place with out negotiation over the Xn, or similar interface. Alternatively, if the gNB 110 de cides to request gNB 112 to suspend its radio link towards the UE panel 2, then negotiation may take place.

In one embodiment, depicted in option 506 of Figure 5, determining the at least one configuration for the UE 120 comprises determining a beam configura tion instructing the UE 120 to apply a wider beam for communication on the iden tified panel 2. Consequently, as shown on Figure 6D, the UE 120 may apply a wide beam (RX and/or Tx) such that it is able to communicate with both cells using the same panel and same beam. In an embodiment, the CS1-RS resources from different TRPs of different cells may be configured in a coordinated manner, so that they are orthogonal e.g. in frequency or code domain. In another related embodiment, the beam from UE 120 and from panel 2 may be configured to comprise nulls in direc tion other than the ones corresponding to the cells providing the multi-connectiv ity.

In one embodiment, implementing one of the options 500 or 504 may not require any inter gNB negotiation (over Xn, for example), while in another em bodiment such negotiation may take place, e.g. when the gNB 110 request the gNB 112 to suspend a beam. Option 502 typically requires negotiation as the TDM pat tern needs to be agreed upon by the associated nodes.

In an embodiment, the gNB may be caused to indicate the determined at least one configuration (either for one or both of the cells, and/or for the UE 120) to the UE 120. In an embodiment, the network (e.g. the gNB 110 and/or the gNB 112) may instruct the UE 120 to de-configure any of the activated options 500-506, e.g. when relevant TRP’s serving beam may be received on different UE panel than panel 2.

Determining beam configuration may comprise determining usage of TX and/or Rx beams. For example, at least one beam may be modified, established, suspended or removed. In other examples, the beams may even be kept the same, but the transmission/reception pattern/resources on the beam(s) may be modi fied.

Figure 7A shows a signalling flow diagram for the option 500 of Figure 5 (i.e. avoiding configuring a serving beam for the identified panel). In step 700 the UE 120 is configured with DC via TRP 2 to cell 1 of gNB 110 and via TRP 3 to cell 2 of gNB 112. In step 702, the UE 120 sends e.g. a LI measurement report to the gNB 110. The measurement report may comprise e.g. Ll-RSRP measurements of SS/PBCH blocks and/or CS1-RS of celll/gNB 110, the UE panel ID corresponding to the reported measurements and the indication. As such, this step may resemble step 300 of Figure 3. In alternative embodiment, the panel ID and the indication may be transmitted without any measurement report. As a result, the gNB 110 may in step 706 refrain from configuring a serving beam that is received by the UE 120 on a panel that the UE 120 is using or can start to use for maintaining radio com munication to at least other cell (e.g. the cell 2 of gNB 112).

In an alternative embodiment, the UE 120 may send such measurement report to gNB 112 in step 704. As a result, the gNB 112 may in step 708 refrain from configuring a serving beam that is received by the UE 120 on a panel that the UE 120 is using or can start to use for maintaining radio communication to at least other cell (e.g. the cell 1 of gNB 110).

In yet one alternative embodiment, both steps 702 and 704 take place, in which case the gNBs 110 and 112 may negotiate regarding which cell will refrain from configuring a serving beam that is received by the UE 120 on the identified panel 2.

Figure 7B illustrates options 502 and 504 of Figure 5. Steps 700, 702 and 704 are as in Figure 7A. Step 704 may be optional. In step 710, the gNB 110 decides to configure a serving beam that will be received by the UE 120 on the iden tified panel 2 which would make the panel 2 associated with multi-connectivity.

As one option, the gNB 110 may in step 712 request the gNB 112 to ap ply TDM (as in step 502) on the cell and TRP relevant to this panel ID 2. In one embodiment, the gNB 110 may provide a proposal for a TDM pattern, which can be either accepted or modified by gNB 112 in the response of step 714. In step 714, the gNB 112 sends and the gNB 110 receives an ACK or NACK as a response to the request. As said, the response may also comprise more information than ACK or NACK, such as modified proposal for the TDM pattern. If the response is NACK, the gNB 110 may in step 716 decide to do nothing or to configure another beam for the UE that will be received by the UE 120 on a panel that is not maintaining any radio communication with another cell or that which has not been reported as a panel that is detecting multiple radio beams from different cells. If the response is ACK in step 714, the gNB 110 may in step 718 configure the UE 120 with a new serving beam as decided in step 710 and decide to command the UE to apply a TDM pattern for reception/transmission. This step may comprise the gNB 110 providing the UE 120 with the TDM pattern for communicating with cells 1 and 2 of gNBs 110 and 112, respectively. For instance, the pattern may specify the indices of the sub- frames in which the UE 112 can communicate with either the gNB 110 or the gNB 112 at a time. In step 722, the UE may then command/trigger/configure the UE 120 to apply the agreed TDM configuration. A message may also be sent from the gNB 110 to the gNB 112 to trigger the earlier agreed TDM pattern active, if the starting time for the TDM has not been decided already in step 712 (or during related ne gotiation between steps 712 and 714).

As another option, the gNB 110 may in step 712 request the gNB 112 to suspend (see step 504) a serving beam on the cell and TRP relevant to this panel ID 2. In step 714, the gNB 112 sends and the gNB 110 receives an ACK or NACK as a response to the request. If the response is NACK, the gNB 110 may in step 716 decide to do nothing or to configure another beam for the UE that will be received by the UE 120 on a panel that is not maintaining any radio communication with another cell. If the response is ACK in step 714, the gNB 110 may in step 720 con figure the UE 120 with a new serving beam as decided in step 710 and decide to command the UE 120 to disable a radio beam from the identified panel towards the gNB 112 (as the gNB 112 has/will suspend it). In step 722, gNB 110 may then com mand/trigger/configure the UE 120 to do so.

In step 724, in an embodiment, the gNB 110 may decide to establish a new serving beam for the UE 120. In such case the configurations determined in steps 718 or 720 may not hold anymore. Consequently, the gNB 110 may in step 724 send a message to the UE 120 that deactivates the previously activated config urations (e.g. de-active the TDM or resume the suspended radio beam from gNB 112). A corresponding message may also be sent to the gNB 112.

In an embodiment, as alternative to requesting the gNB 112 to apply TDM or to suspend the radio link from gNB 112, the gNB 110 may decide to sus pend its own radio link. In this case, there may not be any need to coordinate with gNB 112.

In yet alternative embodiment, the gNB 110 may instruct the UE after step 710 to apply a wide beam (as in step 506 of Figure 5), such that it is able to receive TRP transmission of both gNBs 110, 112 using the same panel and same beam. The wide beam configuration for the UE 120 may also be applied in case a NACK is received as a response in step 714.

Although some embodiments have been explained in the manner that the UE 120 is the receiver and its panel form a receive beam, the embodiments are generally applicable to embodiments where the UE forms a transmit beam and the network node, such as gNB 110 with one of its TRPs form a receive beam for the UE 120.

Looking from a point of view of the UE 120, Figure 8 shows that in step 800, the UE, having multiple antenna panels, detects, at an antenna panel of the UE 120, radio beams from the plurality of cells (e.g. cell 1 or gNB 110 and cell 2 of gNB 112). Thereafter, the UE 120 may in step 802 transmit to at least one access node gNB 110 and/or 112, providing at least one of the cells, the panel identifier of the antenna panel and the indication that the identified antenna panel is detecting ra dio beams from the plurality of cells. As a response to this, the UE 120 may receive in step 804, from the network (e.g. the gNB 110), an indication of a configuration to be applied in at least one of the UE 120 and one or more of the cells. This config uration may correspond to any of the configurations mentioned in connection of Figures 4 to 7, and all the embodiments described therein are applicable to the UE 120 side as well.

The UE 120 may itself also decide on some actions to cope with poten tial or existing multi-connectivity on one panel -scenario (so called UE controlled method). In an embodiment, the UE 120 detects that the UE 120 is or will soon be maintaining a radio communication with at least two cells on a same antenna UE antenna panel. This may take place e.g. by the UE receiving from a cell an indication to switch to a new serving beam that will be received on a panel the UE is already using with another cell. Then, the UE 120 may inform one of cells involved in such existing or potential dual-/multi-connectivity to apply one of the options:

• Option 1: Switch the serving beam of one cell such that it can be received on a UE panel that is not currently maintaining any ra dio communication. Optionally, the UE 120 may indicate to the network the indices of candidate SS/PBCH blocks or CS1-RS. This option may also include the gNBs negotiation in order to come to a conclusion regarding which gNB is switching the radio beam.

• Option 2: Request from the network to apply TDM for the serving beams received on the same panel. The UE 120 may indicate to the network the indices of SS/PBCH blocks or CS1-RS that are corresponding to the serving beams that require TDM resource allocation and coordination. This option may also include the gNBs negotiation in order to come to a conclusion regarding the TDM pattern. The embodiments described in connection of op tion 502 of Figure 5 or Figure 7B may be applicable here.

• Option 3: Request from the network to suspend one of the radio links that are associated with the same UE panel. This option may also include the gNBs negotiation in order to come to a con clusion regarding the suspended beam. The embodiments de scribed in connection of option 504 of Figure 5 or Figure 7B may be applicable here. As explained therein, the suspended radio link can be resumed later once the serving TRP beam can be han dled by another UE panel that is not maintaining any radio com munication.

Figure 9 shows a signalling flow diagram for the UE controlled method. Steps 800, 802, 804 and 810 correspond to steps 700, 702, 704 and 710 of Figure 7B, except the measurement reports in this UE controlled method need not com prise the UE panel and the indication. In step 812, the gNB 110 may command the UE 120 to start using the beam decided in step 810. In step 814, the UE 120 may detect that this new beam may be handled by a panel that is already maintaining a radio communication with at least one other cell.

In step 816, option 1 of above list may be triggered. This may comprise requesting one of the gNBs 110 or 112 (in this case gNB 112) to select a new serv ing beam that will be handled by UE panel not maintaining any radio communica tion. This request may include indices of candidate SS/PBCH blocks or CS1-RS re source indices to network e.g. so that the gNB may configure alternative PDCCH/PDSCH beams based on the indicated DL RS (SS/PBCH or CS1-RS). In step 818, the UE 120 may receive a command for beam switching l.e. the gNB 112 ac cepted the request and may need to reply back to the UE 120 to cause the UE 120 to know which beam will be used with respect to cell 2 of gNB 112. This request of step 818 may be sent to either of the gNBs 110, 112 involved in the multi-connec tivity of one UE antenna panel, although transmission to gNB 112 is shown here. In an embodiment, the UE 120 may propose to the node (to which the request is sent) an alternative serving beam that can be handled on a UE panel that is not maintain ing any radio communication with any other cell. As an alternative to option 1, in step 820, option 2 may be triggered. That is, the UE 120 may request TDM to be applied. The request may carry indices of SS/PBCH blocks or CSI-RS that are corresponding to the serving beams that re quire TDM resource allocation and coordination between the gNBs. This may be needed as these beams cannot be handled simultaneously by the same panel of the UE. This request maybe sent to either of the gNBs 110, 112, although transmission to gNB 112 is shown here.

As yet one alternative, option 3 may be triggered in step 822 where the UE 120 may request to suspend one of the radio beams of gNB 1/celll and gNB 112/cell2. The request may carry indices of SS/PBCH blocks or CSI-RS that are cor responding to the serving beams that require TDM resource allocation and coordi nation between the gNBs. This may be needed as these beams cannot be handled simultaneously by the same panel of the UE. This request may be sent to either of the gNBs 110, 112, although transmission to gNB 112 is shown here.

In step 824, the gNBs 110, 112 may negotiate regarding the request of option 2 or option 3. E.g. the receiving gNB 112 may request the gNB 110 to apply the TDM with respect to the relevant UE panel or suspend a radio link beam to the relevant UE panel. Step 826 may comprise an ACK or NACK to the negotiation. Step 828 may comprise the gNB 112 responding to the UE with a command to apply TDM (Option 2) or to suspend/de-active at least temporarily one of the radio links.

In yet one embodiment not shown, the UE 120 may decide to apply a wider beam for communication on the panel that is maintaining at least two radio connections, so as to be able to receive/transmit on both network beams with one wide UE beam.

An embodiment, as shown in Figure 10, provides an apparatus 10 com prising a control circuitry (CTRL) 12, such as at least one processor, and at least one memory 14 including a computer program code (software), wherein the at least one memory and the computer program code (software), are configured, with the at least one processor, to cause the apparatus to carry out any one of the above- described processes. The memory may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The memory may comprise a database for stor ing data.

The apparatus may further comprise radio interface (TRX) 16 compris ing hardware and/or software for realizing communication connectivity according to one or more communication protocols. The TRX may provide the apparatus with communication capabilities to communicate with the UE, for example. The appa ratus may also comprise a user interface 18 comprising, for example, at least one keypad, a microphone, a touch display, a display, a speaker, etc. The user interface may be used to control the apparatus by the user.

In an embodiment, the apparatus 10 may be or be comprised in a net work node, such as in gNB/gNB-CU/gNB-DU of 5G. In an embodiment, the appa ratus 10 is or is comprised in the network node 110. The apparatus may be caused to execute the functionalities of some of the above described processes. In an em bodiment, the apparatus 10 is or is comprised in the gNB 110.

The control circuitry 12 may comprise a configuration determination circuitry 20 for determining any of the configurations mentioned, e.g. a beam con figuration, TDM configuration, CS1-RS configuration, according to any of the em bodiments. This may comprise the apparatus negotiating with another apparatus, for example. The control circuitry 12 may further comprise a beam control circuitry 22 for establishing or modifying radio beams, according to any of the embodiments.

It should be appreciated that future networks may utilize network func tions virtualization (NFV) which is a network architecture concept that pro-poses virtualizing network node functions into "building blocks" or entities that may be operationally connected or linked together to provide services. A virtualized net work function (VNF) may comprise one or more virtual machines running com puter program codes using standard or general type servers instead of customized hardware. Cloud computing or data storage may also be utilized. In radio commu nications, this may mean node operations to be carried out, at least partly, in a cen tral/centralized unit, CU, (e.g. server, host or node) operationally coupled to dis tributed unit, DU, (e.g. a radio head/node). It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. It should also be understood that the distribution of labour between core net-work operations and base station operations may vary depending on implementation.

In an embodiment, the server may generate a virtual network through which the server communicates with the radio node. In general, virtual networking may involve a process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network. Such virtual network may provide flexible distribution of operations be tween the server and the radio head/node. In practice, any digital signal processing task may be performed in either the CU or the DU and the boundary where the responsibility is shifted between the CU and the DU may be selected according to implementation.

Therefore, in an embodiment, a CU-DU architecture is implemented. In such case the apparatus 10 may be comprised in a central unit (e.g. a control unit, an edge cloud server, a server) operatively coupled (e.g. via a wireless or wired network) to a distributed unit (e.g. a remote radio head/node). That is, the central unit (e.g. an edge cloud server) and the radio node may be stand-alone apparatuses communicating with each other via a radio path or via a wired connection. Alter natively, they may be in a same entity communicating via a wired connection, etc. The edge cloud or edge cloud server may serve a plurality of radio nodes or a radio access networks. In an embodiment, at least some of the described processes may be performed by the central unit. In another embodiment, the apparatus 10 may be instead comprised in the distributed unit, and at least some of the described pro cesses may be performed by the distributed unit.

In an embodiment, the execution of at least some of the functionalities of the apparatus 10 may be shared between two physically separate devices (DU and CU) forming one operational entity. Therefore, the apparatus may be seen to depict the operational entity comprising one or more physically separate devices for executing at least some of the described processes. In an embodiment, such CU- DU architecture may provide flexible distribution of operations between the CU and the DU. In practice, any digital signal processing task may be performed in ei ther the CU or the DU and the boundary where the responsibility is shifted between the CU and the DU may be selected according to implementation. In an embodi ment, the apparatus 50 controls the execution of the processes, regardless of the location of the apparatus and regardless of where the processes/functions are car ried out.

An embodiment, as shown in Figure 11, provides an apparatus 50 com prising a control circuitry (CTRL) 52, such as at least one processor, and at least one memory 54 including a computer program code (software), wherein the at least one memory and the computer program code (software), are configured, with the at least one processor, to cause the apparatus to carry out any one of the above- described processes. The memory may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The memory may comprise a database for stor ing data. The apparatus may further comprise radio interface (TRX) 56 compris ing hardware and/or software for realizing communication connectivity according to one or more communication protocols. The TRX may provide the apparatus with communication capabilities to communicate with the UE, for example. The TRX may comprise several antenna panels, for establishing wireless connectivity to the network. The apparatus may also comprise a user interface 58 comprising, for ex ample, at least one keypad, a microphone, a touch display, a display, a speaker, etc. The user interface may be used to control the apparatus by the user.

In an embodiment, the apparatus 50 may comprise the terminal device of a communication system, e.g. a user terminal (UT), a computer (PC), a laptop, a tabloid computer, a cellular phone, a mobile phone, a communicator, a smart phone, a palm computer, a mobile transportation apparatus (such as a car), a household appliance, sensor, or any other communication apparatus, commonly called as UE in the description. Alternatively, the apparatus is comprised in such a terminal device. Further, the apparatus may be or comprise a module (to be at tached to the UE) providing connectivity, such as a plug-in unit, an "USB dongle", or any other kind of unit. The unit may be installed either inside the UE or attached to the UE with a connector or even wirelessly. In an embodiment, the apparatus 50 is or is comprised in the UE 120. The apparatus may be caused to execute the func tionalities of some of the above described processes.

The control circuitry 52 may comprise an antenna panel control cir cuitry 60 for controlling radio beam of the apparatus, for detecting possible multi connectivity at one of the plurality of antenna panels, for applying a wide beam in at least one antenna panel, etc., according to any of the embodiments. The control circuitry 12 may further comprise an access control circuitry 62 for controlling ra dio access to the network via any of the antenna panels, according to any of the embodiments. The control circuitry 12 may further comprise a configuration de termination circuitry 64 for determining or at least determining to propose a con figuration to be applied, e.g. requesting to propose a TDM pattern or a beam sus pension, according to any of the embodiments.

In an embodiment, an apparatus carrying out at least some of the em bodiments described comprises at least one processor and at least one memory including a computer program code, wherein the at least one memory and the com puter program code are configured, with the at least one processor, to cause the apparatus to carry out the functionalities according to any one of the embodiments described. According to an aspect, when the at least one processor executes the computer program code, the computer program code causes the apparatus to carry out the functionalities according to any one of the embodiments described. Accord ing to another embodiment, the apparatus carrying out at least some of the embod iments comprises the at least one processor and at least one memory including a computer program code, wherein the at least one processor and the computer pro gram code perform at least some of the functionalities according to any one of the embodiments described. Accordingly, the at least one processor, the memory, and the computer program code form processing means for carrying out at least some of the embodiments described. According to yet another embodiment, the appa ratus carrying out at least some of the embodiments comprises a circuitry includ ing at least one processor and at least one memory including computer program code. When activated, the circuitry causes the apparatus to perform the at least some of the functionalities according to any one of the embodiments described.

As used in this application, the term 'circuitry' refers to all of the follow ing: (a) hardware-only circuit implementations, such as implementations in only analog and/or digital circuitry, and (b) combinations of circuits and soft- ware (and/or firmware), such as (as applicable): (i) a combination of processor(s) or (ii) portions of processor(s)/software including digital signal processor(s), software, and memory(ies) that work together to cause an apparatus to perform various functions, and (c) circuits, such as a microprocessor(s) or a portion of a micropro- cessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. This definition of 'circuitry' applies to all uses of this term in this application. As a further example, as used in this application, the term 'circuitry' would also cover an implementation of merely a processor (or mul tiple processors) or a portion of a processor and its (or their) accompanying soft ware and/or firmware. The term 'circuitry' would also cover, for example and if applicable to the particular element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device, or another network device.

In an embodiment, at least some of the processes described may be car ried out by an apparatus comprising corresponding means for carrying out at least some of the described processes. Some example means for carrying out the pro cesses may include at least one of the following: detector, processor (including dual-core and multiple-core processors), digital signal processor, controller, re ceiver, transmitter, encoder, decoder, memory, RAM, ROM, software, firmware, dis play, user interface, display circuitry, user interface circuitry, user interface software, display software, circuit, antenna, antenna circuitry, and circuitry.

The techniques and methods described herein may be implemented by various means. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or combinations thereof. For a hardware implementation, the appa ratuses) of embodiments may be implemented within one or more application- specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programma ble gate arrays (FPGAs), processors, controllers, micro-controllers, microproces sors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, the implementation can be car ried out through modules of at least one chip set (e.g. procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit and executed by processors. The memory unit may be imple mented within the processor or externally to the processor. In the latter case, it can be communicatively coupled to the processor via various means, as is known in the art. Additionally, the components of the systems described herein may be rear ranged and/or complemented by additional components in order to facilitate the achievements of the various aspects, etc., described with regard thereto, and they are not limited to the precise configurations set forth in the given figures, as will be appreciated by one skilled in the art.

Embodiments as described may also be carried out in the form of a com puter process defined by a computer program or portions thereof. Embodiments of the methods described may be carried out by executing at least one portion of a computer program comprising corresponding instructions. The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, which may be any entity or device capable of carrying the program. For example, the computer program may be stored on a com puter program distribution medium readable by a computer or a processor. The computer program medium may be, for example but not limited to, a record me dium, computer memory, read-only memory, electrical carrier signal, telecommu nications signal, and software distribution package, for example. The computer program medium may be a non-transitory medium. Coding of software for carrying out the embodiments as shown and described is well within the scope of a person of ordinary skill in the art. Following is a list of some aspects of the invention.

According to a first aspect, there is provided an apparatus, comprising at least one processor and at least one memory including a computer program code, wherein the at least one memory and the computer program code are config ured, with the at least one processor, to cause an access node providing a first cell to perform: receiving, from a user equipment, over the first cell a panel identifier indicating an antenna panel of the user equipment and an indication that the iden tified antenna panel is detecting radio beams from the first cell and from at least one cell other than the first cell; determining, based on the reception, at least one configuration for at least one of the user equipment and one or more of the cells.

Various embodiments of the first aspect may comprise at least one fea ture from the following bulleted list:

• wherein the panel identifier is unique among the first cell and the at least one other cell.

• wherein the panel identifier and the indication are received in a radio measurement report message.

• wherein determining the at least one configuration comprises negotiating with at least one other access node providing the at least one other cell, wherein the negotiation comprises indicat ing the received panel identifier to the at least one other access node.

• wherein the at least one memory and the computer program code are configured, with the at least one processor to cause the access node further to perform: indicating the determined at least one configuration to the user equipment.

• wherein the at least one memory and the computer program code are configured, with the at least one processor to cause the access node further to perform: determining, based on the re ception, a reference signal transmission configuration for the first cell and/or for the at least one other cell such that reference signals are transmitted for the identified antenna panel substan tially simultaneously from the first cell and from the at least one other cell; sending the reference signals to the user equipment for the identified antenna panel based on the determined refer ence signal transmission configuration; triggering a receive beam sweep at the user equipment on the identified antenna panel based on determined reference signal transmission config uration.

• wherein the reference signal transmission configuration of the first cell comprises repetitively transmitting the reference sig nals.

• wherein the at least one memory and the computer program code are configured, with the at least one processor to cause the access node further to perform: determining a beam configura tion for at least one of the cells, wherein the beam configuration comprises at least one of the cells to refrain from setting up a beam that would be associated with the identified antenna panel.

• wherein the at least one memory and the computer program code are configured, with the at least one processor to cause the access node further to perform: determining a beam configura tion for at least one of the cells, wherein the beam configuration comprises at least temporarily suspending at least one beam to wards the identified antenna panel.

• wherein the at least one memory and the computer program code are configured, with the at least one processor to cause the access node further to perform: determining a time-division multiplexing configuration between the first cell and the at least one other cell such that at a time only one cell communicates with the identified antenna panel of the user equipment; com municating with the user equipment according to the deter mined time-division multiplexing configuration.

• wherein the at least one memory and the computer program code are configured, with the at least one processor to cause the access node further to perform: determining a beam configura tion instructing the user equipment to apply a wider beam for communication on the identified antenna panel.

According to a second aspect, there is provided an apparatus, compris ing: at least one processor and at least one memory including a computer program code, wherein the at least one memory and the computer program code are config ured, with the at least one processor, to cause a user equipment having multiple antenna panels to perform: detecting, at an antenna panel of the user equipment, radio beams from a plurality of cells; transmitting, to at least one access node providing at least one of the cells: a panel identifier of the antenna panel of the user equipment and an indication that the identified antenna panel is detecting radio beams from the plurality of cells; as response to the transmission, receiving an in dication of a configuration to be applied in at least one of the user equipment and one or more of the cells.

Various embodiments of the second aspect may comprise at least one feature from the bulleted list under the first aspect and/or at least one feature from the following bulleted list:

• wherein the panel identifier is unique among the plurality of cells.

• wherein the panel identifier and the indication are transmitted in a radio measurement report message.

• wherein the at least one memory and the computer program code are configured, with the at least one processor to cause the user equipment further to perform: receiving a reference signal transmission configuration for the plurality of cells such that ref erence signals are received by the identified antenna panel sub stantially simultaneously from at least two cells of the plurality of cells; sweeping a receive beam on the identified antenna panel based on determined reference signal transmission configura tion; determining, based on the sweeping of the receive beam, at least one beam for communication with the at least two cells of the plurality of cells.

• wherein the at least one memory and the computer program code are configured, with the at least one processor to cause the user equipment further to perform: receiving one of a time-divi sion multiplexing configuration between plurality of cells such that at a time only one cell communicates with the identified an tenna panel of the user equipment, a beam configuration for at least one of the plurality of cells, wherein the beam configuration comprises at least one of the cells to refrain from setting up a beam that would be associated with the identified antenna panel, a beam configuration for at least one of the plurality of cells, wherein the beam configuration comprises at least temporarily suspending at least one beam towards the identified antenna panel, or a beam configuration for the user equipment instructing to apply a wider beam for communication on the identified antenna panel; and communicating with at least one of the plurality of cells according to the received configuration.

• wherein the apparatus is or is comprised in the user equipment.

According to a third aspect, there is provided a method at an access node providing a first cell, the method comprising: receiving, from a user equip ment, over the first cell a panel identifier indicating an antenna panel of the user equipment and an indication that the identified antenna panel is detecting radio beams from the first cell and from at least one cell other than the first cell; deter mining, based on the reception, at least one configuration for at least one of the user equipment and one or more of the cells.

Various embodiments of the third aspect may comprise at least one fea ture from the bulleted list under the first aspect.

According to a fourth aspect, there is provided method at a user equip ment, the method comprising: detecting, at an antenna panel of the user equip ment, radio beams from a plurality of cells; transmitting, to at least one access node providing at least one of the cells a panel identifier of the antenna panel of the user equipment and an indication that the identified antenna panel is detecting radio beams from the plurality of cells; as response to the transmission, receiving an in dication of a configuration to be applied in at least one of the user equipment and one or more of the cells.

Various embodiments of the fourth aspect may comprise at least one feature from the bulleted list under the second aspect.

According to a fifth aspect, there is provided a computer program prod uct embodied on a distribution medium readable by a computer and comprising program instructions which, when loaded into an apparatus, execute the method according to the third aspect. Various embodiments of the fifth aspect may com prise at least one feature from the bulleted list under the first aspect.

According to a sixth aspect, there is provided a computer program prod uct embodied on a distribution medium readable by a computer and comprising program instructions which, when loaded into an apparatus, execute the method according to the fourth aspect. Various embodiments of the sixth aspect may com prise at least one feature from the bulleted list under the second aspect.

According to a seventh aspect, there is provided a computer program product comprising program instructions which, when loaded into an apparatus, execute the method according to the third aspect. Various embodiments of the seventh aspect may comprise at least one feature from the bulleted list under the first aspect.

According to an eight aspect, there is provided a computer program product comprising program instructions which, when loaded into an apparatus, execute the method according to the fourth aspect. Various embodiments of the eight aspect may comprise at least one feature from the bulleted list under the sec ond aspect.

According to a ninth aspect, there is provided an apparatus, comprising means for performing the method according to the third aspect, and/or means con figured to cause a user equipment to perform the method according to the third aspect. Various embodiments of the ninth aspect may comprise at least one feature from the bulleted list under the first aspect.

According to a tenth aspect, there is provided an apparatus, comprising means for performing the method according to the fourth aspect, and/or means configured to cause a user equipment to perform the method according to the fourth aspect. Various embodiments of the tenth aspect may comprise at least one feature from the bulleted list under the second aspect.

According to an eleventh aspect, there is provided computer system, comprising: one or more processors; at least one data storage, and one or more computer program instructions to be executed by the one or more processors in association with the at least one data storage for carrying out the method according to the third aspect and/or the method according to the fourth aspect.

Even though the invention has been described above with reference to an example according to the accompanying drawings, it is clear that the invention is not restricted thereto but can be modified in several ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, the embodiment. It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. Further, it is clear to a person skilled in the art that the described embodiments may, but are not required to, be com bined with other embodiments in various ways.

Claims

1. An apparatus, comprising: at least one processor and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause an access node providing a first cell to perform: receiving, from a user equipment, over the first cell:

• a panel identifier indicating an antenna panel of the user equip ment; and

• an indication that the identified antenna panel is detecting radio beams from the first cell and from at least one cell other than the first cell; determining, based on the reception, at least one configuration for at least one of the user equipment and one or more of the cells.

2. The apparatus of claim 1, wherein the panel identifier is unique among the first cell and the at least one other cell.

3. The apparatus of any of claims 1 to 2, wherein the panel identifier and the indication are received in a radio measurement report message.

4. The apparatus of any of claims 1 to 3, wherein determining the at least one configuration comprises negotiating with at least one other access node providing the at least one other cell, wherein the negotiation comprises indicating the received panel identifier to the at least one other access node.

5. The apparatus of any of claims 1 to 4, wherein the at least one memory and the computer program code are configured, with the at least one pro cessor to cause the access node further to perform: indicating the determined at least one configuration to the user equip ment.

6. The apparatus of any of claims 1 to 5, wherein the at least one memory and the computer program code are configured, with the at least one pro- cessor to cause the access node further to perform: determining, based on the reception, a reference signal transmission configuration for the first cell and/or for the at least one other cell such that refer ence signals are transmitted for the identified antenna panel substantially simulta neously from the first cell and from the at least one other cell; sending the reference signals to the user equipment for the identified antenna panel based on the determined reference signal transmission configura tion; triggering a receive beam sweep at the user equipment on the identified antenna panel based on determined reference signal transmission configuration.

7. The apparatus of claim 6, wherein the reference signal transmission configuration of the first cell comprises repetitively transmitting the reference sig nals.

8. The apparatus of any of claims 1 to 7, wherein the at least one memory and the computer program code are configured, with the at least one pro cessor to cause the access node further to perform: determining a beam configuration for at least one of the cells, wherein the beam configuration comprises at least one of the cells to refrain from setting up a beam that would be associated with the identified antenna panel.

9. The apparatus of any of claims 1 to 7, wherein the at least one memory and the computer program code are configured, with the at least one pro cessor to cause the access node further to perform: determining a beam configuration for at least one of the cells, wherein the beam configuration comprises at least temporarily suspending at least one beam towards the identified antenna panel.

10. The apparatus of any of claims 1 to 7, wherein the at least one memory and the computer program code are configured, with the at least one pro- cessor to cause the access node further to perform: determining a time-division multiplexing configuration between the first cell and the at least one other cell such that at a time only one cell communi cates with the identified antenna panel of the user equipment; communicating with the user equipment according to the determined time-division multiplexing configuration.

11. The apparatus of any of claims 1 to 7, wherein the at least one memory and the computer program code are configured, with the at least one pro cessor to cause the access node further to perform: determining a beam configuration instructing the user equipment to ap ply a wider beam for communication on the identified antenna panel.

12. An apparatus, comprising: at least one processor and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause a user equipment having multiple antenna panels to perform: detecting, at an antenna panel of the user equipment, radio beams from a plurality of cells; transmitting, to at least one access node providing at least one of the cells:

• a panel identifier of the antenna panel of the user equipment; and

• an indication that the identified antenna panel is detecting radio beams from the plurality of cells; as response to the transmission, receiving an indication of a configura tion to be applied in at least one of the user equipment and one or more of the cells.

13. The apparatus of claim 12, wherein the panel identifier is unique among the plurality of cells.

14. The apparatus of any of claims 12 to 13, wherein the panel identifier and the indication are transmitted in a radio measurement report message.

15. The apparatus of any of claims 12 to 14, wherein the at least one memory and the computer program code are configured, with the at least one pro cessor to cause the user equipment further to perform: receiving a reference signal transmission configuration for the plurality of cells such that reference signals are received by the identified antenna panel sub stantially simultaneously from at least two cells of the plurality of cells; sweeping a receive beam on the identified antenna panel based on de termined reference signal transmission configuration; determining, based on the sweeping of the receive beam, at least one beam for communication with the at least two cells of the plurality of cells.

16. The apparatus of any of claims 12 to 15, wherein the at least one memory and the computer program code are configured, with the at least one pro cessor to cause the user equipment further to perform: receiving one of:

• a time-division multiplexing configuration between plurality of cells such that at a time only one cell communicates with the identified antenna panel of the user equipment;

• a beam configuration for at least one of the plurality of cells, wherein the beam configuration comprises at least one of the cells to refrain from setting up a beam that would be associated with the identified antenna panel.

• a beam configuration for at least one of the plurality of cells, wherein the beam configuration comprises at least temporarily suspending at least one beam towards the identified antenna panel; and

• a beam configuration for the user equipment instructing to apply a wider beam for communication on the identified antenna panel; communicating with at least one of the plurality of cells according to the received configuration.

17. The apparatus of any of claims 12 to 16, wherein the apparatus is or is comprised in the user equipment.

18. A method at an access node providing a first cell, the method com prising: receiving, from a user equipment, over the first cell:

• a panel identifier indicating an antenna panel of the user equip ment; and

19. A method at a user equipment, the method comprising: detecting, at an antenna panel of the user equipment, radio beams from a plurality of cells; transmitting, to at least one access node providing at least one of the cells:

• a panel identifier of the antenna panel of the user equipment; and

20. A computer program product comprising program instructions which, when loaded into an apparatus, execute the method according to claim 18 or the method according to claim 19.

21. A computer program product embodied on a distribution medium readable by a computer and comprising program instructions which, when loaded into an apparatus, execute the method according to claim 18 or the method accord ing to claim 19.

22. An apparatus, comprising means for performing the method accord ing to claim 18 or the method according to claim 19.